feat: update preferredLocations field to List<String> across staff-related entities and mutations

- Changed preferredLocations from AnyValue to List<String> in GetStaffByIdStaff, GetStaffByUserIdStaffs, ListStaffStaffs, and UpdateStaffVariablesBuilder classes.
- Updated JSON serialization/deserialization for preferredLocations to handle List<String>.
- Modified Staff entity to include preferredLocations as List<String>.
- Adjusted ProfileSetupBloc and PersonalInfoBloc to accommodate changes in preferredLocations.
- Updated PersonalInfoRepositoryImpl to handle preferredLocations as List<String>.
- Refactored PersonalInfoContent and PersonalInfoForm to use locations instead of address.
- Updated GraphQL mutations and schema to reflect the new List<String> type for preferredLocations.

backend/dataconnect/schema/staff.gql

@@ -63,7 +63,7 @@ type Staff @table(name: "staffs") {
   bio: String
   skills: Any #changed it for staffRole
   industries: Any
-  preferredLocations: Any
+  preferredLocations: [String]
   maxDistanceMiles: Int 
   languages: Any
   itemsAttire: Any